Reel

ABSTRACT

The present invention provides a reel which includes: a hub, around an outer periphery face of which a recording tape is wound; an annular first flange disposed at one axial direction end portion of the hub; an annular second flange disposed at the other axial direction end portion of the hub; a plurality of first pad portions protruding into the hub from the first flange, the first pad portions being engaged with the hub to be relatively non-rotatable; and a plurality of second pad portions protruding into the hub from the second flange, the plurality of second pad portions being welded to the plurality of first pad portions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of International Application No. PCT/JP2011/075214, filed Nov. 1, 2011, the disclosure of which is incorporated herein by reference in its entirety. Further, this application claims priority from Japanese Patent Application No. 2011-042336, filed Feb. 28, 2011, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a reel on which a recording tape such as a magnetic tape or the like is wound.

2. Related Art

Heretofore, a recording tape cartridge has been known in which a recording tape such as a magnetic tape or the like, which is principally used as an information recording and replaying medium for computers and the like (data backup), is wound on a reel, and the reel is singly accommodated in a case.

A reel with a three-piece structure is known as a reel to be accommodated in this recording tape cartridge. In the three-piece structure, an upper circular tube portion is formed at an inner periphery portion of an upper flange, a lower circular tube portion is formed at an inner periphery portion of a lower flange, the upper circular tube portion and lower circular tube portion are welded together, and a hub is sheathed around the outer periphery face side of the upper circular tube portion and lower circular tube portion (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2007-299437).

However, in the reel disclosed in Japanese Patent Application Laid-Open (JP-A) No. 2007-299437, the upper circular tube portion and lower circular tube portion are welded along the whole periphery thereof. Therefore, process efficiency in a welding process cannot necessarily be considered to be excellent. In addition, a turning preventer that prevents the hub from rotating relative to the upper and lower flanges must be separately formed.

SUMMARY

The present invention provides a reel that may improve process efficiency in a welding process.

A reel according to a first aspect of the present invention includes: a hub, around an outer periphery face of which a recording tape is wound; an annular first flange disposed at one axial direction end portion of the hub; an annular second flange disposed at the other axial direction end portion of the hub; plural first pad portions protruding into the hub from the first flange, the first pad portions being engaged with the hub to be relatively non-rotatable; and plural second pad portions protruding into the hub from the second flange, the plural second pad portions being welded to the plural first pad portions.

According to a reel in accordance with the first aspect, because the reel is assembled by the plural first pad portions protruding into the hub interior from the first flange being welded to the plural second pad portions protruding into the hub interior from the second flange, process efficiency in a welding process may be improved. Moreover, because the first flange and the second flange may be made incapable of rotating relative to the hub by the first pad portions being engaged with the hub to disable relative rotation, there is no need to form a separate turning preventer.

In a reel according to a second aspect of the present invention, in the reel according to the first aspect, the first pad portions are engaged with an inner periphery face side of the hub.

According to a reel in accordance with the second aspect, the first pad portions and second pad portions may be welded at the inner periphery face side of the hub. Therefore, the first flange and second flange may be welded more securely than in a structure in which first pad portions and second pad portions are welded at the center side of a hub. The meaning of the term “inner periphery face side of the hub” as used herein is not limited to positions adjacent to the inner periphery face of the hub but includes positions that are a little toward the radial direction inner side from the inner periphery face of the hub.

In a reel according to a third aspect of the present invention, the reel according to the first aspect further includes a penetrating hole formation portion that is integrally formed at an inner periphery face of the hub and in which penetrating holes are formed, wherein relative rotation between the first flange and second flange and the hub is disabled by at least the first pad portions being fitted into the penetrating holes.

According to a reel in accordance with the third aspect, the first pad portions and second pad portions may be welded with ease. Moreover, relative rotation between the first flange and second flange and the hub may be disabled with a simple structure.

In a reel according to a fourth aspect of the present invention, the reel according to the first aspect further includes a circular plate-shaped reinforcement portion that is integrally formed at an inner periphery face of the hub so as to be coaxial with the hub, and in an outer periphery portion of which penetrating holes are formed, wherein relative rotation between the first flange and second flange and the hub is disabled by at least the first pad portions being fitted into the penetrating holes.

According to a reel in accordance with the fourth aspect, the first pad portions and second pad portions may be welded with ease. Moreover, relative rotation between the first flange and second flange and the hub may be disabled with a simple structure. Further, a hub with a higher stiffness (strength) than a hub that does not include a reinforcement portion can be provided.

In a reel according to a fifth aspect of the present invention, in the reel according to the fourth aspect, a fastening portion for fastening to a rotary member of a drive device is formed at the reinforcement portion.

According to a reel in accordance with the fifth aspect, the reel may be directly installed in a drive device.

In a reel according to a sixth aspect of the present invention, in the reel according to the third aspect, a gap is formed between a radial direction outer side wall face of the penetrating holes and a radial direction outer side wall face of at least the first pad portions.

According to a reel in accordance with the sixth aspect, because gaps are formed between the radial direction outer side wall faces of the penetrating holes and the radial direction outer side wall faces of the at least the first pad portions, when a recording tape is wound on the hub, a deformation of the hub caused by winding force of the recording tape may be absorbed by the gaps.

In a reel according to a seventh aspect of the present invention, in the reel according to the third aspect, the first pad portions are structured in plural different kinds of shape, the second pad portions are structured in plural kinds of shape that correspond with the first pad portions, and the penetrating holes are formed in plural kinds of shape that correspond with at least the first pad portions.

According to a reel in accordance with the seventh aspect, a combination in which the first pad portions of the first flange are welded to the second pad portions of the second flange is specifically determined in the circumferential direction. In particular, if the first pad portions and the second pad portions are respectively formed in corresponding shapes with equal spacings, the first pad portions and second pad portions are unlikely to become slanted. Thus, surface runout of the first flange and the second flange may be suppressed or prevented.

In a reel according to an eighth aspect of the present invention, in the reel according to the first aspect, the first flange at which the first pad portions are provided and the second flange at which the second pad portions are provided are formed in the same shape.

According to a reel in accordance with the eighth aspect, the first flange and the second flange may be formed by a single mold. Hence, fabrication costs may be reduced.

In a reel according to a ninth aspect of the present invention, in the reel according to the seventh aspect, each of the first pad portions and the second pad portions includes an identical flat-shaped plate.

According to a reel in accordance with the ninth aspect, the first pad portions and second pad portions may be formed with ease. Hence, fabrication costs may be reduced.

In a reel according to a tenth aspect of the present invention, in the reel according to the ninth aspect, energy directors are provided with a welding surface of each of the first pad portions and the second pad portions, and the energy directors are provided intermittently in a circumferential direction and are spaced by a predetermined interval in a radial direction.

According to a reel in accordance with the tenth aspect, welding areas are increased and the energy of ultrasonic oscillations for melting the energy directors, may be efficiently transmitted to the energy directors.

In a reel according to a eleventh aspect of the present invention, in the reel according to the ninth aspect, energy directors are provided from an end portion substantially to a middle portion in a circumferential direction with a welding surface of each of the first pad portions and the second pad portions, such that when the welding surfaces of the first pad portions are superposed with the welding surfaces of the second pad portion, the energy directors of the first pad portions do not face with the energy directors of the second pad portions.

According to a reel in accordance with the eleventh aspect, welding areas are increased and the energy of ultrasonic oscillations for melting the energy directors, may be efficiently transmitted to the energy directors. Further, the shapes of the energy directors formed on the first pad portion and the second pad portions may be simplified.

In a reel according to a twelfth aspect of the present invention, in the reel according to the ninth aspect, the penetrating holes are formed with shapes the same as the first pad portions and the second pad portions, and a plate thickness of the penetrating hole formation portion is twice plate thicknesses of the first pad portions and the second pad portions.

According to a reel in accordance with the twelfth aspect, the penetrating holes may be formed with ease. Hence, fabrication costs may be reduced.

In a reel according to a thirteenth aspect of the present invention, in the reel according to the seventh aspect, each of the first pad portions and the second pad portions includes first welding ribs that is formed with a longer and narrow shape and second welding ribs that is formed with a shorter and narrow shape, and the first welding ribs and the second welding ribs are provided alternating at equal intervals.

According to a reel in accordance with the thirteenth aspect, the first pad portions and second pad portions may be formed with ease. Hence, fabrication costs may be reduced.

In a reel according to a fourteenth aspect of the present invention, in the reel according to the thirteenth aspect, first energy directors are formed at a radial direction outer side on the first welding ribs, and second energy directors are formed at a radial direction inner side on the second welding ribs.

According to a reel in accordance with the fourteenth aspect, welding areas are increased and the energy of ultrasonic oscillations for melting the energy directors, may be efficiently transmitted to the energy directors.

In a reel according to a fifteenth aspect of the present invention, in the reel according to the thirteenth aspect, the first welding ribs and the second welding ribs protrude to the same heights, and a plate thickness of the penetrating hole formation portion is twice protrusion height of the first welding ribs and second welding ribs.

According to a reel in accordance with the fifteenth aspect, the first welding ribs and the second welding ribs are unlikely to cause slanting in the radial direction. Thus, surface runout of the first flange and the second flange may be suppressed or prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described in detail based on the following figures, wherein:

FIG. 1 is a perspective diagram showing a pair of reels installed in a drive device.

FIG. 2 is an exploded perspective diagram of a reel in accordance with a first exemplary embodiment.

FIG. 3 is an exploded perspective sectional diagram in which principal portions of the reel in accordance with the first exemplary embodiment are shown magnified.

FIG. 4 is a sectional perspective diagram of the reel in accordance with the first exemplary embodiment.

FIG. 5 is a sectional diagram in which principal portions of the reel in accordance with the first exemplary embodiment are shown magnified.

FIG. 6A is a perspective diagram showing an example of the shapes of energy directors formed at protrusion portions of the reel in accordance with the first exemplary embodiment.

FIG. 6B is a perspective diagram showing another example of the shapes of the energy directors formed at the protrusion portion of the reel in accordance with the first exemplary embodiment.

FIG. 7 is an exploded perspective diagram of a reel in accordance with a second exemplary embodiment.

FIG. 8 is a plan diagram showing welding ribs that are formed at protrusion portions of the reel in accordance with the second exemplary embodiment.

FIG. 9 is a perspective diagram showing a reel hub of the reel in accordance with the second exemplary embodiment viewed from beneath.

FIG. 10 is a sectional diagram showing a state in which the welding ribs formed at the protrusion portions of the reel in accordance with the second exemplary embodiment are mutually welded.

FIG. 11 is a sectional diagram in which principal portions of the reel in accordance with the second exemplary embodiment are shown magnified.

DETAILED DESCRIPTION

Herebelow, exemplary embodiments relating to the present invention are described in detail in accordance with the drawings. For convenience in the descriptions, the arrow UP in FIG. 1 represents an upward direction, the arrow DO represents a downward direction, and a rotation axis direction of reels 10 and 20 according to the present exemplary embodiments is referred to as an up-and-down direction (or height direction). Firstly, a first exemplary embodiment is described.

The reels 10 and 20 according to the present exemplary embodiment are fabricated of a synthetic resin such as, for example, polycarbonate (PC). As shown in FIG. 1, the reels 10 and 20 are provided as a pair inside a casing 52 of a drive device 50 (of which only a floor plate 54 and three support pillars 56 are shown in FIG. 1).

The reel 10 is used for feeding out a recording tape T and the reel 20 is used for taking up the recording tape T. While the recording tape T is being fed out from the reel 10 and taken up at the reel 20, the recording tape T slides against a recording/replay head 60. Thus, data is recorded on the recording tape T by the recording/replay head 60 and/or data that has been recorded at the recording tape T is replayed.

A plural number (four in the drawing, in sets of two) of tape guides 58 are rotatably provided on the floor plate 54 at the two sides of the recording/replay head 60. The recording tape T being unwound from the reel 10 and taken up at the reel 20 is guided by the tape guides 58.

The reels 10 and 20 are structured with reel hubs 12 and 22, upper flanges 14 and 24, lower flanges 16 and 26, and reinforcement portions 18 and 28 (see FIG. 2 to FIG. 5). The reel hubs 12 and 22 structure axial central portions of the reels 10 and 20 and have substantially circular tube shapes. The upper flanges 14 and 24 have annular shapes and serve as first flanges provided at upper end portion sides of the reel hubs 12 and 22. The lower flanges 16 and 26 have annular shapes and serve as second flanges provided at lower end portion sides of the reel hubs 12 and 22. The reinforcement portions 18 and 28 have substantially circular plate shapes that serve as penetrating hole formation portions, which are integrally continuous with height (axial) direction middle portions of inner periphery faces of the reel hubs 12 and 22.

The recording tape T, which is a magnetic tape or the like and serves as an information recording and replaying medium, is wound around the outer periphery face of the reel hub 12 of the reel 10. Width direction end portions of the recording tape T are retained by the upper flange 14 and the lower flange 16. The recording tape T that has been fed out from the reel 10 is taken up onto the outer periphery face of the reel hub 22 of the reel 20, and the width direction end portions thereof are retained by the upper flange 24 and the lower flange 26.

The meaning of the term “substantially circular tube shape” as used in the present exemplary embodiments includes generally circular rod shapes in which the shapes of the outer periphery faces (winding faces) of the reel hubs 12 and 22 on which the recording tape T is wound are formed as bulging cylinder shapes or the like, hollow shapes that are not purely circular tube shapes, in which ribs or the like are provided protruding from the inner periphery face sides of the reel hubs 12 and 22, and so forth.

A motor that serves as a drive source (not shown in the drawings) is provided at the drive device 50. A pair of rotary members (not shown in the drawings) transmit rotary driving force from a rotary shaft of the motor (not shown in the drawings). The respective rotary members are rotatably provided in a pair of aperture portions (not shown in the drawings) that are formed in the casing 52 (the floor plate 54) of the drive device 50. The reinforcement portions 18 and 28 of the reels 10 and 20 are integrally fixed (fastened) to the respective rotary members by unillustrated screws.

The structures of the reel 10 and the reel 20 are identical. Accordingly, the reel 10 is taken as an example and described below. As shown in FIG. 2 to FIG. 5, an upper circular tube portion 15 is integrally formed at an inner periphery edge portion of the upper flange 14 of the reel 10. The upper circular tube portion 15 extends downward by a predetermined height, to be inserted into the reel hub 12. A lower circular tube portion 17 is integrally formed at an inner periphery edge portion of the lower flange 16. The lower circular tube portion 17 extends upward by a predetermined height, to be inserted into the reel hub 12.

A plural number (for example, six) of protrusion portions 32 with flat plate shapes, which serve as first pad portions, are integrally formed at equal intervals at a lower end portion of the upper circular tube portion 15. The protrusion portions 32 protrude to the radial direction inner side (toward a rotation center portion of the reel 10). Similarly, a plural number (the same as that of the protrusion portions 32, which is six in this case) of protrusion portions 34 with flat plate shapes, which serve as second pad portions, are integrally formed at equal intervals at an upper end portion of the lower circular tube portion 17. The protrusion portions 34 protrude to the radial direction inner side (toward the rotation center portion of the reel 10).

The protrusion portions 32 and the protrusion portions 34 have identical shapes, and the height of the upper circular tube portion 15 and the height of the lower circular tube portion 17 are the same. That is, the upper flange 14 and the lower flange 16 are formed in identical shapes. Therefore, the upper flange 14 and the lower flange 16 are structures that may be formed by a single mold, and that may reduce fabrication costs.

The height of the upper circular tube portion 15 and the height of the lower circular tube portion 17 with respect to the reel hub 12 are set to heights such that, when the reel hub 12 is sheathed around the outer periphery face sides of the upper circular tube portion 15 and the lower circular tube portion 17, no gap is formed between an upper end face of the reel hub 12 and a lower face of the upper flange 14 or between a lower end face of the reel hub 12 and an upper face of the lower flange 16, as shown in FIG. 5. Therefore, deformation of the upper flange 14 and the lower flange 16 by winding force of the recording tape T can be suppressed.

As shown in FIG. 2 to FIG. 4, a plural number (the same as that of the protrusion portions 32 and 34, which is six in this case) of penetrating holes 30 are formed in the reinforcement portion 18 of the reel hub 12 at an outer periphery edge portion side thereof (positions adjacent to the inner periphery face of the reel hub 12). The penetrating holes 30 are formed at equal intervals, with shapes the same as the protrusion portions 32 and 34. A plate thickness of the region of the reinforcement portion 18 in which the penetrating holes 30 are formed is twice the plate thicknesses of the protrusion portions 32 and 34 (see FIG. 5).

In this structure, as shown in FIG. 4 and FIG. 5, the protrusion portions 32 of the upper flange 14 are fitted into the penetrating holes 30 formed in the reinforcement portion 18 from above, and the protrusion portions 34 of the lower flange 16 are fitted into the penetrating holes 30 from below. Thus, the reel hub 12 is made non-rotatable relative to the upper flange 14 and the lower flange 16 (rotating (turning) is prevented). By the protrusion portions 32 and protrusion portions 34 being ultrasonically welded, the upper flange 14 and the lower flange 16 are joined together and the reel hub 12 is integrally mounted at the outer periphery face side of the upper circular tube portion 15 and the lower circular tube portion 17.

As shown in FIG. 6A, two rows of energy directors (hereinafter referred to as EDs 37) that serve as welding fluxes are provided protruding from a welding surface of each of the protrusion portions 32 and 34. The EDs 37 of each protrusion portion 32 or 34 are provided intermittently in the circumferential direction (at equal intervals) and are spaced by a predetermined interval in the radial direction. Accordingly, welding areas are increased and the energy of ultrasonic oscillations for melting the EDs 37 may be efficiently transmitted to the EDs 37.

As shown in FIG. 6B, the EDs 37 may be provided from an end portion substantially to a middle portion in the circumferential direction (i.e., on substantially half) of the welding surface of each protrusion portion 32 or 34. Thus, it may be that when the welding surfaces of the protrusion portions 32 are superposed with the welding surfaces of the protrusion portions 34, the EDs 37 of the protrusion portions 32 do not face (overlap) with the EDs 37 of the protrusion portions 34.

That is, it may be that the EDs 37 formed substantially at a circumferential direction half of the welding surface of one protrusion portion 32 or 34 face the welding surface of another protrusion portion 32 or 34 from the other end portion substantially to the middle portion of the other welding surface (i.e., substantially the other half at which the EDs 37 thereof are not formed). Accordingly, the shapes of the EDs 37 formed on the protrusion portions 32 and 34 may be simplified.

As shown in FIG. 2 to FIG. 4, three screw hole portions 36 that serve as a fastening portion are formed at equal intervals on a concentric circumference of the reinforcement portion 18. Screws for fastening to the rotary member of the drive device 50 are inserted through the screw hole portions 36. A protrusion portion 38 is integrally formed at a lower face side of each screw hole portion 36. The protrusion portion 38 protrudes downward in a circular tube shape that is coaxial with the screw hole portion 36 (and communicates with the screw hole portion 36). With this structure, positioning of the reel 10 (the reinforcement portion 18) in the up-and-down (height) direction with respect to the rotary member is implemented by the protrusion portions 38 abutting against an upper face of the rotary member.

A circular hole portion 40 is formed in the rotation center portion of the reinforcement portion 18. An output shaft portion (not shown in the drawings) protruding from the rotary member of the drive device 50 is inserted (fitted) into the circular hole portion 40. Thus, with this structure, positioning of the reel 10 (the reinforcement portion 18) in the radial direction with respect to the rotary member (i.e., centering) is implemented.

A plural number (for example, three) of protruding portions (not shown in the drawings) are protrudingly provided at equal intervals on a concentric circumference of the rotary member. A plural number of recessed portions 42 (the same number as that of the protruding portions, which is three in this case) are formed at equal intervals on a concentric circumference in the lower face of the reinforcement portion 18, at the radial direction inner side relative to the screw hole portions 36 (a region at which the plate thickness is large). The protruding portions fit into the recessed portions 42. Thus, with this structure, positioning of the reel 10 (the reinforcement portion 18) with respect to the rotary member in the circumferential direction is implemented, and the screw hole portions 36 may be matched up with screw boss portions (not shown in the drawings) formed at the rotary member.

Now, operation of the reel 10 with the structure described above is described. As mentioned above, the reel 10 is fabricated by the plural (the same number as the penetrating holes 30) protrusion portions 32 of the upper flange 14 and the plural (the same number as the penetrating holes 30) protrusion portions 34 of the lower flange 16 being fitted into the plural penetrating holes 30 formed in the reinforcement portion 18, and the protrusion portions 32 and protrusion portions 34 being joined together by ultrasonic welding.

That is, in a welding process for fabrication of the reel 10, it is sufficient for just the protrusion portions 32 and protrusion portions 34 to be ultrasonically welded. Therefore, compared to a structure in which the lower end face of the upper circular tube portion 15 and the upper end face of the lower circular tube portion 17 are ultrasonically welded over the whole periphery, process efficiency may be improved (a process time required for the welding may be shortened). Moreover, because the protrusion portions 32 and 34 are welded at the inner periphery face side of the reel hub 12, the upper flange 14 and lower flange 16 may be more securely welded than in a structure in which the protrusion portions 32 and 34 are welded at the reel hub 12 center side.

Furthermore, by the ultrasonic welding of the protrusion portions 32 of the upper flange 14 and the protrusion portions 34 of the lower flange 16 that are fitted into the penetrating holes 30 formed in the reinforcement portion 18 of the reel hub 12, the upper flange 14 and lower flange 16 may be joined together and may be mounted to make the reel hub 12 non-rotatable with respect to the upper flange 14 and lower flange 16.

Therefore, there is no need to separately form a turning preventer to make the reel hub 12 and the upper and lower flanges 14 and 16 relatively non-rotatable. Thus, compared to a structure in which a turning preventer for making the reel hub 12 and the upper and lower flanges 14 and 16 relatively non-rotatable is separately formed, fabrication of molds for molding the parts may be simplified and mold fabrication costs may be reduced.

Moreover, because the upper flange 14 and the lower flange 16 have the same shape (symmetry between the upper and the lower), a single mold is sufficient for fabricating the upper flange 14 and the lower flange 16. Thus, compared to a structure in which the shapes of the upper flange 14 and the lower flange 16 are different and a mold for the upper flange 14 and a mold for the lower flange 16 are separately required, fabrication costs may be further reduced.

The protrusion portions 32 that are plurally (in the same number as the penetrating holes 30) formed at equal intervals on the upper flange 14 and the protrusion portions 34 that are plurally (in the same number as the penetrating holes 30) formed at equal intervals on the lower flange 16 are fitted into the penetrating holes 30 that are plurally formed at equal intervals in the reinforcement portion 18 of the reel hub 12. Thus, looseness (and axial misalignment) between the reel hub 12 and the upper and lower flanges 14 and 16 may be suppressed or prevented.

The fastening portion (the screw hole portions 36) for fastening to the drive device (rotary member) is provided at the reinforcement portion 18 that is formed integrally with the reel hub 12 around which the magnetic tape T is wound. Therefore, compared to a structure in which a portion for fastening to a drive device is a separate body from the reel hub 12, stiffness (strength) of the reel hub 12 may be assured and running stability of the magnetic tape T may be improved.

The reel 20 is the same. The reels 10 and 20 are mounted and fixed to the Os of the drive device 50 with screws. That is, screws are inserted through the screw hole portions 36 of the reinforcement portions 18 and 28 of the reels 10 and 20 and threaded into the screw boss portions of the rotary members, and thus the reinforcement portions 18 and 28 of the reels 10 and 20 are fastened to the rotary members. Thus, the reels 10 and 20 may be directly installed in the drive device 50.

Next, a second exemplary embodiment is described. Portions that are the same as in the above-described first exemplary embodiment are assigned the same reference numerals and are not described in detail (nor operations thereof). The second exemplary embodiment too is described using the reel 10 as an example, and the reel 20 is again the same.

As shown in FIG. 7 to FIG. 11, in the upper flange 14 and the lower flange 16 of the reel 10 according to the second exemplary embodiment, protrusion portions 33 and 35 are integrally formed to protrude from the lower end portion of the upper circular tube portion 15 and the upper end portion of the lower circular tube portion 17. Each of the protrusion portions 33 and 35 protrudes in an annular shape to the radial direction inner side.

As shown in more detail in FIG. 8, long, narrow first welding ribs 46 and shorter, narrow second welding ribs 48 are provided protruding from a welding surface (lower face) of the protrusion portion 33 of the upper flange 14 (i.e., the upper circular tube portion 15) in plural numbers alternating at equal intervals (in the illustrated case, three of each at 120° intervals, making a total of six ribs). The first welding ribs 46 and second welding ribs 48 serve as the first pad portions.

Similarly, the long, narrow first welding ribs 46 and shorter, narrow second welding ribs 48 are provided protruding from a welding surface (upper face) of the protrusion portion 35 of the lower flange 16 (i.e., the lower circular tube portion 17) in plural numbers alternating at equal intervals (in the illustrated case, three of each at 120° intervals, making a total of six ribs). These first welding ribs 46 and second welding ribs 48 serve as the second pad portions. Respective single rows of the EDs 37 are formed at the first welding ribs 46 and the second welding ribs 48, at the radial direction outer side on the first welding ribs 46 and at the radial direction inner side on the second welding ribs 48.

As illustrated in detail in FIG. 9 and FIG. 10, the penetrating holes 30 in the reinforcement portion 18 of the reel 10 according to the second exemplary embodiment are formed at positions set a little toward the radial direction inner side from the inner periphery face of the reel hub 12, and are structured such that the first welding ribs 46 and second welding ribs 48 can be respectively fitted therein.

Thus, the upper flange 14 and the lower flange 16 are joined together by the first welding ribs 46 of the protrusion portion 33 being welded to the second welding ribs 48 of the protrusion portion 35 and the second welding ribs 48 of the protrusion portion 33 being welded to the first welding ribs 46 of the protrusion portion 35.

Accordingly, step portions 44 are formed at each penetrating hole 30, alternating between the upper face side and the lower face side of the reinforcement portion 18. The step portions 44 are formed at both of circumferential direction end edge portions of each penetrating hole 30. The step portions 44 are for making up differences in length in the circumferential direction between the first welding ribs 46 and the second welding ribs 48 (allowing for the two circumferential direction end edge portions of each first welding rib 46 being longer in the circumferential direction than the second welding rib 48).

That is, the first welding ribs 46 and the second welding ribs 48 protrude to the same heights, and the plate thickness of the reinforcement portion 18 at the region in which the penetrating holes 30 are formed is twice the protrusion height of the first welding ribs 46 and second welding ribs 48. The height of each step portion 44 is the same as the protrusion height of the first welding rib 46 (which is half of the plate thickness of the reinforcement portion 18 at the region in which the penetrating holes 30 are formed).

Thus, in this structure, as shown in FIG. 10, the first welding ribs 46 that are fitted into the penetrating holes 30 and the second welding ribs 48 that are fitted into the penetrating holes 30 may be welded by the respective EDs 37 that have positional relationships so as not to face one another in the up-and-down direction (to be offset from one another in the radial direction and not overlap).

Thus, with the structure in which the first welding ribs 46 at which the EDs 37 are formed at the radial direction outer side and the second welding ribs 48 at which the EDs 37 are formed at the radial direction inner side are superposed and joined (the structure in which the EDs 37 do not overlap with one another), the first welding ribs 46 and the second welding ribs 48 are unlikely to cause slanting in the radial direction. Thus, surface runout of the upper flange 14 and the lower flange 16 may be suppressed or prevented.

As shown in FIG. 11, a gap S1 in the radial direction is formed between each of wall faces 18A at the radial direction outer sides of the penetrating holes 30 and each of wall faces 46A and 48A at the radial direction outer sides of the first welding ribs 46 and second welding ribs 48 fitted into the penetrating holes 30. A gap S2 in the radial direction is also formed between an inner periphery face 12A of the reel hub 12 and outer periphery faces 15A and 17A of the upper circular tube portion 15 and the lower circular tube portion 17.

At the inner periphery face side of the reel hub 12, the substantially circular plate-shaped reinforcement portion 18 that is concentric with the reel hub 12 is integrally provided to be continuous. Therefore, the radial direction stiffness (strength) of the reel hub 12 is improved compared to a reel hub in which the reinforcement portion 18 is not integrally provided to be continuous (not shown in the drawings). Consequently, deformation of the reel hub 12 by winding force of the recording tape T may be suppressed, and effects on the upper flange 14 and the lower flange 16 may be prevented.

At the same time, because the above-mentioned gaps S1 and S2 are formed in the radial direction, deformation of the reel hub 12 by the winding force of the recording tape T may be absorbed by these gaps S1 and S2. Therefore, effects on the upper flange 14 and the lower flange 16 may be further prevented. Herein, the gaps S1 and S2 are set at, for example, between 0.05 mm and 0.5 mm.

Hereabove, the reels 10 and 20 according to the present exemplary embodiments are described on the basis of the attached drawings, but the reels 10 and 20 according to the present exemplary embodiments are not limited to the reels shown in the drawings; designs may be modified as appropriate within a scope not departing from the spirit of the present invention. For example, the structures in which both the first pad portions (the protrusion portions 32 or the first welding ribs 46 and second welding ribs 48) and the second pad portions (the protrusion portions 34 or the first welding ribs 46 and second welding ribs 48) are together fitted into the penetrating holes 30 in the reinforcement portion 18 or 28 are not limiting; structures in which one or both of the first pad portions and the second pad portions are fitted in are possible.

However, in a structure in which both the first pad portions and the second pad portions are together fitted into the penetrating holes 30 of the reinforcement portion 18 or 28, the upper flange 14 at which the first pad portions are provided and the lower flange 16 at which the second pad portions are provided may be formed in the same shape, which is desirable. Further, in the illustrated case the upper flange 14 and lower flange 16 are joined together by the welding ribs 46 and 48 of two kinds with different shapes, but the upper flange 14 and lower flange 16 may be joined together by welding ribs of three or more kinds with different shapes.

In this case it is desirable for the welding ribs with different shapes to be formed alternatingly at equal intervals. Thus, surface runout of the upper flange 14 and the lower flange 16 may be suppressed or prevented. Further, the protrusion portions 38 are not limited to being formed at the lower faces of the screw hole portions 36 coaxially with the screw hole portions 36, and may be formed at the lower face of the reinforcement portion 18 or 28 on a different concentric circumference from the screw hole portions 36.

The recessed portions 42 may be formed in the rotary member and the protruding portions formed at the reinforcement portion 18 or 28 to implement positioning in the circumferential direction (matching up the positions of the screw hole portions 36 at the reinforcement position 18 or 28 with the screw boss portions at the rotary member). The numbers of the recessed portions 42 (and protruding portions) and of the screw hole portions 36 (and screw boss portions) are not limited to three. Furthermore, although not shown in the drawings, the reels 10 and 20 according to the present exemplary embodiment may also be employed in recording tape cartridges in which only one reel is accommodated in a case. 

What is claimed is:
 1. A reel comprising: a hub, around an outer periphery face of which a recording tape is wound; an annular first flange disposed at one axial direction end portion of the hub; an annular second flange disposed at the other axial direction end portion of the hub; a plurality of first pad portions protruding into the hub from the first flange, the first pad portions being engaged with the hub to be relatively non-rotatable; and a plurality of second pad portions protruding into the hub from the second flange, the plurality of second pad portions being welded to the plurality of first pad portions.
 2. The reel according to claim 1, wherein the first pad portions are engaged with an inner periphery face side of the hub.
 3. The reel according to claim 1, further comprising a penetrating hole formation portion that is integrally formed at an inner periphery face of the hub and in which penetrating holes are formed, wherein relative rotation between the first flange and second flange and the hub is disabled by at least the first pad portions being fitted into the penetrating holes.
 4. The reel according to claim 1, further comprising a circular plate-shaped reinforcement portion that is integrally formed at an inner periphery face of the hub so as to be coaxial with the hub, and in an outer periphery portion of which penetrating holes are formed, wherein relative rotation between the first flange and second flange and the hub is disabled by at least the first pad portions being fitted into the penetrating holes.
 5. The reel according to claim 4, wherein a fastening portion for fastening to a rotary member of a drive device is formed at the reinforcement portion.
 6. The reel according to claim 3, wherein a gap is formed between a radial direction outer side wall face of the penetrating holes and a radial direction outer side wall face of at least the first pad portions.
 7. The reel according to claim 3, wherein the first pad portions are structured in a plurality of different kinds of shape, the second pad portions are structured in a plurality of kinds of shape that correspond with the first pad portions, and the penetrating holes are formed in a plurality of kinds of shape that correspond with at least the first pad portions.
 8. The reel according to claim 1, wherein the first flange at which the first pad portions are provided and the second flange at which the second pad portions are provided are formed in the same shape.
 9. The reel according to claim 7, wherein each of the first pad portions and the second pad portions includes an identical flat-shaped plate.
 10. The reel according to claim 9, wherein energy directors are provided with a welding surface of each of the first pad portions and the second pad portions, and the energy directors are provided intermittently in a circumferential direction and are spaced by a predetermined interval in a radial direction.
 11. The reel according to claim 9, wherein energy directors are provided from an end portion substantially to a middle portion in a circumferential direction with a welding surface of each of the first pad portions and the second pad portions, such that when the welding surfaces of the first pad portions are superposed with the welding surfaces of the second pad portion, the energy directors of the first pad portions do not face with the energy directors of the second pad portions.
 12. The reel according to claim 9, wherein the penetrating holes are formed with shapes the same as the first pad portions and the second pad portions, and a plate thickness of the penetrating hole formation portion is twice plate thicknesses of the first pad portions and the second pad portions.
 13. The reel according to claim 7, wherein each of the first pad portions and the second pad portions includes first welding ribs that is formed with a longer and narrow shape and second welding ribs that is formed with a shorter and narrow shape, and the first welding ribs and the second welding ribs are provided alternating at equal intervals.
 14. The reel according to claim 13, wherein first energy directors are formed at a radial direction outer side on the first welding ribs, and second energy directors are formed at a radial direction inner side on the second welding ribs.
 15. The reel according to claim 13, wherein the first welding ribs and the second welding ribs protrude to the same heights, and a plate thickness of the penetrating hole formation portion is twice protrusion height of the first welding ribs and second welding ribs. 